test(runtime): add issue #463 phase 1 groundwork

[Orinks]

Summary

• add Phase 1 migration-safety tests for legacy alert and notification-event state behavior
• add a lean RuntimeStateManager scaffold rooted at state/runtime_state.json
• keep portable/settings copy flows excluding runtime state files

Testing

• pytest tests/test_alert_manager.py tests/test_notification_event_manager.py tests/test_runtime_state_manager.py tests/test_settings_dialog_portable_copy.py

Closes #463